Key characters in popular CBS' shows, including “2 Broke Girls” and “Mike and Molly,” have regularly made jokes about minorities that some critics and advocacy groups argued were offensive.

Those concerns have been primarily met with a "no comment" from CBS, which has long had a spotty record when it comes to increasing diversity in prime time, as well as in casting minorities in leading or prominent roles on comedies and dramas.

CBS stayed mum when Native American organizations lashed out last March at a joke on "Mike and Molly." During the episode, Mike’s bigoted mother Peggy, played by Rondi Reed, quipped, “Arizona? Why would I move to Arizona? It’s nothing but a furnace full of drunk Indians.”

Erny Zah, a spokesperson for the Navajo Nation, which occupies part of Arizona, said in an interview with ABCNews.com, said she was outraged by the joke: “It’s offensive, it’s derogatory, it’s deplorable. Ignorance is one thing, but this must have passed through a lot of eyes before it appeared on a network show.”

Another comedy, “2 Broke Girls,” has also been heavily criticized by advocacy groups for its depiction of one of its main characters, Han Lee, the immigrant Korean owner of a downscale Brooklyn diner. Lee, played by Matthew Moy, speaks with heavy broken English (“She blond—hair so shiny. Good for business,” said Lee in a first season episode while explaining why he hired a blond waitress).

Michael Patrick King, who created the series with Whitney Cummings, heightened the controversy over the show last year when he told a group of TV reporters that he had latitude to make fun of “outsiders” because he is gay.

Though the offending comments on "Big Brother" were made during the show’s online feed, CBS aired them on Sunday’s broadcast. The controversy has given the show's sagging ratings a boost. "Big Brother" host Julie Chen, who is married to CBS Corp. Chief Executive Leslie Moonves, said on her daytime show “The Talk” that she was personally “stung” and “hurt” by the "Big Brother" comments, comparing them to “bullying.”

Asked about the differing responses to potentially offending comments on its scripted and reality shows, CBS executives replied, "No comment."